Recent studies from our laboratory have shown that infusion of ATP-MgCl2 to animals following hepatic ischemia, renal ischemia or severe sepsis improved cell function and the survival of animals. The precise mechanism of the beneficial effect of ATP-MgCl2, however, remains unknown. We plan to determine the mechanism by which ATP-MgCl2 improves cell function and the survival of animals following various adverse circulatory conditions. We hope to determine the mechanism of ATP translocation during control conditions and determine if this is effected during shock. We also plan to characterize a probable ATP transport system and determine whether the ATP uptake process requires energy for its operation. The possibility that ATP-MgCl2 prevents the leakage of various intracellular enzymes during adverse circulatory conditions will also be examined. We also plan to determine whether red blood cell sodium, potassium levels are affected during sepsis and if so, what is the agent responsible for it. Kidneys will be perfused with ATP-MgCl2 for prolonged periods of time to determine if renal function could be preserved. We will also attempt to determine whether prolonged starvation lowers the ability of the host defense mechanism. We also plan to alter prostaglandin production and determine if this would have any effect on the survival of animals following shock.